JP2000120789A - Damper device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized damper device capable of reducing twisting oscillation of a crank shaft, effectively reducing driving noises of an engine, attachable to the crank shaft inside a crank case, excellent in high durability and reliability. SOLUTION: This damper device is provided with an inertial ring, a damper hub, and a circular rubber member seizedly fixed to the inertial ring. A ratio between an inertial moment Id of the damper and an equivalent inertial moment Ie of a crank shaft system, that is, Id/Ie ranges between 0.05 and 0.1. A ratio between a twisting characteristic frequency fd and a twisting equivalent characteristic frequency fe of the crank shaft system, that is fd/fe ranges between 0.95 and 1.1. A loss factor η of the circular rubber member in a damper 30 ranges between 0.2 and 0.4. The inertial ring of the damper is made of steel member such as STKM (by JIS). The circular rubber member adopts acrylic rubber, nitrile butadien rubber excellent in heat resistance and oil resistance, for securing durability and reliability against operation inside a crank case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damper device mounted on a crankshaft of a four-cylinder engine and capable of reducing torsional vibration of the crankshaft and reducing operating noise caused by the torsional vibration. It is.

[0002]

2. Description of the Related Art Conventionally, a damper hub is coaxially mounted to a tip portion of a crankshaft of a four-cylinder engine by an appropriate fixing means such as a bolt, and is mounted on a radially outer portion of the hub via an annular rubber member. in one provided a damper device having an inertia ring which is, in order to reduce operating noise caused by the bending vibration of the crankshaft, bending and natural frequency f _db damper, the equivalent of the crankshaft based bending natural vibration A damper device in which the ratio f _db / f _eb to the number f _eb is set to 0.7 to 1.0 has already been proposed by the present applicant and disclosed in Japanese Patent Application Laid-Open No. Hei 4-302741. (Hereinafter, in some cases, the damper device described in the above publication is referred to as a previously proposed device.)

The above-mentioned proposed device focuses on reduction of operating noise caused by bending vibration of a crankshaft, that is, vibration whose amplitude is generated in a direction perpendicular to the crankshaft axis, and reduces torsional vibration of the crankshaft. It is not intended to reduce the operating noise by reducing it, and therefore, the ratio of the natural frequency of the damper with respect to torsional vibration to the equivalent natural frequency of the crankshaft system, the moment of inertia of the damper and the equivalent moment of inertia of the crankshaft system By setting the ratio of the annular rubber member and the loss factor of the annular rubber member in the damper to specific ranges, the torsional vibration of the crankshaft system can be effectively reduced, and the engine operating noise caused by the torsional vibration can be reduced. No attempt has been made to do so.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is an operation which is caused by torsional vibration of a four-cylinder engine by effectively reducing the torsional vibration of the crankshaft. A main object of the present invention is to provide a damper device that can significantly reduce noise, and that is small, lightweight, and easy to attach to a crankshaft.

Another object of the present invention is that the crankshaft can be mounted on a web portion inside the crankcase, so that it is not necessary to increase the entire length of the crankshaft for mounting the damper device, and it is also possible to improve durability and durability. An object of the present invention is to provide a damper device mounted on a crankshaft of a four-cylinder engine with excellent reliability.

[0006]

In order to achieve the above object, the present invention provides a damper hub coaxially mounted on a crankshaft of a four-cylinder engine, and an inertia ring mounted on the damper hub via an annular rubber member. I _d : inertia moment of the damper I _e : equivalent inertia moment of the crankshaft system f _d : torsional natural frequency of the damper _fe : torsional equivalent natural frequency of the crankshaft system η: when the loss factor of the annular rubber member, the inertia moment ratio _I d _{/ I} e = _0.05~
0.1, torsional natural frequency ratio f _d / f _e = 0.95-1.
1. It proposes a damper device characterized in that the loss factor η is set to 0.2 to 0.4.

By setting the inertia moment ratio, the natural frequency ratio, and the loss factor of the damper device mounted on the crankshaft of the four-cylinder engine within the above ranges,
As compared to the case without the damper device, the torsional vibration is 40 ~
There is provided a damper device which has an effect capable of being reduced by 70%, and which is capable of greatly reducing the operation noise caused by torsional vibration, and which is excellent in durability and reliability with small size and light weight.

Further, in the present invention, it is preferable that the inertial ring is made of a steel material and the annular rubber member is made of a rubber material having excellent heat resistance and oil resistance. As described above, by making the inertial ring from a steel material such as STKM, the inertial ring is not crushed even if the annular rubber member is broken, as compared with the inertial ring usually made of cast iron, Also, by making the annular rubber member from a rubber material having excellent heat resistance and oil resistance such as acrylic rubber (ACM or the like) or hydrogenated nitrile butadiene rubber (H-NBR or the like), the damper device can be formed into a crankcase of a crankshaft. The durability and the reliability can be ensured even if the crankshaft is mounted on a portion accommodated therein, for example, a web portion. As a result, the overall length of the crankshaft can be shortened.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIGS. First, in the first embodiment shown in FIGS. 1 and 2, reference numeral 10 generally indicates a crankshaft of a four-cylinder engine for a vehicle, and the crankshafts 10 are arranged at intervals in an axial direction. Five crank journals 12, four crank pins 14 disposed between adjacent crank journals 12, and a crank web disposed on both sides of each crank pin 14 for connecting the crank pins 14 and the crank journals 12. 1
6 and a balance weight 18 integrally formed with an appropriate crank web 16.

In the crankshaft 10, oil passages 20 and 22 for supplying oil to the outer peripheral sliding surfaces of the crank journal 12 and the crankpin 14 are formed. At the front end, a crank gear 24 for driving a timing gear train for driving accessories such as a camshaft and a fuel injection pump is fixed, and at the rear end of the crankshaft 10, a flywheel is mounted. The wheel 26 is mounted.

The crank web 16 connecting the crank pin 14 corresponding to the first cylinder # 1 of the crankshaft 10 and the frontmost crank journal 12 has a short cylindrical circular support portion 28 coaxially with the crank axis. Is formed, and a damper indicated generally by reference numeral 30 is attached to the circular support portion 28.

As shown in an enlarged sectional view of a main part of FIG. 3, the damper 30 has a cylindrical portion 32a which is externally fitted to the circular support portion 28 and is press-fitted and fixed, and a disk extending radially outward. A damper hub 32 having a portion 32b, and an inertia ring 36 as an inertia body mounted on the disk portion 32b of the damper hub 32 via an annular rubber member 34,
The annular rubber member 34 is vulcanized and bonded to opposing side surfaces of the disk portion 32b and the inertia ring 36.

[0013] Between the disc portion 32b and the crank web 16, it is assumed that the disc portion 32b vibrates and comes into contact with the side surface of the crank web 16 to cause fretting wear or noise. To prevent it beforehand, and the disk part 3
In order to promote cooling of 2b, a gap t of preferably about 1 mm is provided. In the figure, reference numeral 38 denotes a balance hole formed on the side surface of the inertia ring 36 opposite to the annular rubber member 34 in order to balance the inertia ring 36 statically.

The crankshaft 10 on which the damper 30 is mounted
When the torsion vibration occurs during operation of the four-cylinder engine having the above, the inertia ring 36 elastically deforms the annular rubber member 34 with respect to the damper hub 32 which rotates integrally with the crankshaft 10 and relatively rotates around the crankshaft axis. As a result, vibration energy is converted into heat energy, and torsional vibration is reduced.

Crankshaft 10 with damper 30 mounted
, The moment of inertia of the damper 30 is I _d , the equivalent moment of inertia of the crankshaft system is I _e , the torsional natural frequency of the damper 30 is f _d , the torsional equivalent natural frequency of the crankshaft system is f _e , when the loss factor of the annular rubber member 34 eta, below as will be described in detail, the moment of inertia ratio _{μ = I d / I e =} 0.05~0.1, torsional natural frequency ratio lambda = _{f d} / _f e = 0.95~1.1, is set in the loss factor η = 0.2~0.4.

First, FIG. 4 is a diagram showing the inertia moment ratio μ on the horizontal axis and the torsional amplitude and the weight W of the damper 30 on the vertical axis. As shown by the solid curve theta _c in FIG torsional amplitude of the crank shaft 10 is increasing rapidly inertia moment ratio μ is 0.05 or less, becomes substantially constant at least 0.1, the weight of the damper 30 Only W increases. On the other hand, as shown by dotted curve theta _d in the figure, the relative amplitude of the damper (torsional amplitude of the inertial ring 36 against the damper hub 32), the moment of inertia ratio μ increases rapidly at 0.05, 0. In the region from 05 to 0.1, it gradually decreases,
Is exceeded, the decrease in the amplitude is small and substantially saturates, and only the weight W of the damper 30 increases.

In view of the above circumstances, in order to ensure the durability of the crankshaft 10 and to prevent the annular rubber member 34 which substantially affects the durability of the damper 30 in particular, and to reduce the weight of the damper 30. The ratio between the moment of inertia of the damper 30 and the equivalent moment of inertia of the crankshaft 10 system is reasonably set to μ = 0.05 to 0.1.

Next, FIG. 5 the horizontal axis represents frequency, and the vertical axis represents the torsional amplitude theta _c of the crankshaft 10, the equivalent natural frequency of the natural frequency f _d and the crankshaft system of the damper 30 about torsional vibrations shows the relationship between the crankshaft amplitude theta _c and the vibration frequency of section I and section II of the case where the λ ratio of the number f _e changed variously. As shown, as the natural frequency ratio λ increases from 0.95 shown by the solid line to 1.0 shown by the dotted line, and further to 1.1 shown by the dashed line, the node I resonance peak value increases. , And the peak value moves to the higher frequency side. On the other hand, the node II resonance peak value decreases from the node I peak value as λ increases from 0.95 to 1.0 and further to 1.1 (however, the decrease amount is small at λ = 0.95) and the peak value increases. The value shifts to higher frequencies. For reference, the amplitude of the crankshaft 10 without the damper 30 is shown, and the resonance peak is one and the peak value is extremely large as shown in the figure. By mounting the damper 30, the resonance peak of the crankshaft amplitude theta _c are distributed on both sides of Section I and Section II of the amplitude curve without the damper, and the peak value decreases 40% to 70%.

[0019] Figure 6 the horizontal axis represents frequency, and the vertical axis represents the relative amplitude theta _d damper 30, the resonance peak of Section I and Section II when was varied the natural frequency ratio λ 2 shows the relationship between the vibration frequency and the vibration frequency. As shown, as the natural frequency ratio λ increases from 0.95 (indicated by a solid line) to 1.0 (indicated by a dotted line) and further to 1.1 (indicated by a dashed line), the I-node resonance peak value Increases, and the peak value moves to the higher frequency side. On the other hand, the node II resonance peak value decreases as λ increases from 0.95 to 1.0 and further to 1.1, and the peak value moves to the higher frequency side. On the other hand, the resonance peak value of the node II is as follows.
From 1.0 to 1.1, and further to 1.1, the frequency shifts to the higher frequency side. However, when λ = 0.95, contrary to the crankshaft amplitude θ _c, it increases from the peak value of the node I.

FIG. 7 shows the resonance peaks of the nodes I and II in FIGS. 5 and 6 by taking the natural frequency ratio λ on the horizontal axis and the relative amplitudes of the crankshaft 10 and the damper 30 on the vertical axis. have the meanings indicated to organize the change of values, in each of the crankshaft amplitude theta _c and the damper relative amplitude theta _d, shows the I clause resonance peak value by a solid line, a section II resonance peak value by a dotted line.

FIG. 8 shows the natural frequency ratio λ on the horizontal axis.
FIG. 8 is a diagram showing the maximum torsional amplitude on the vertical axis, that is, the larger peak value including the resonance peaks of the nodes I and II in FIG. 7. As shown, in both the crankshaft amplitude and the damper relative amplitude, the natural frequency ratio λ
Are extremely large in the region where is less than 0.95 and exceeds 1.1, respectively, and in the region of 0.95 or more and 1.1 or less, the amplitude is sufficiently small, respectively. Therefore, λ = 0.95-
By setting the value to 1.1, the durability against the torsional vibration of the crankshaft 10 can be ensured, and the durability of the damper 30, particularly the annular rubber member 34 can be ensured.

Next, FIG. 9 shows the loss factor η of the annular rubber member 34 in the damper 30 on the abscissa and the torsional amplitude on the ordinate, torsional amplitude θ _c of the crankshaft 10 (shown by a solid line in the figure). And the relative amplitude θ _{d of the} damper 30 (shown by a dotted line in the figure).

[0023] As illustrated, in the region of loss factor η is less than 0.2, the crankshaft torsional amplitude theta _c and the damper relative amplitude becomes both large, especially the latter of the damper relative amplitude theta _d
Is undesirably large because it has an adverse effect on the durability of the damper 30. Furthermore, loss factor η is in the region of more than 0.4, both of the crankshaft amplitude theta _c and the damper relative amplitude theta _d is substantially saturate, the performance improvement of the durability can not be expected. Therefore, the loss factor η is
It is reasonable to set the value in the range of 0.2 or more and 0.4 or less, particularly from the viewpoint of the durability of the annular rubber member 34 and the like.

As described above, the damper 3 for torsional vibration
0, that is, the above moment of inertia ratio μ = I _d / I _e =
0.05 to 0.1, the moment of inertia ratio λ = f _d / f _e =
0.95 to 1.1, loss factor η of the annular rubber member 36
= 0.2 to 0.4, the torsional amplitude of the crankshaft 10 is set to 40 to 7 as compared with a crankshaft without the damper 30 as shown in an example in FIG.
It can be reduced by about 0%, and as a result, the operating noise of the engine can be significantly reduced.

Referring again to FIGS. 1 to 3, the damper 30 is mounted coaxially with the crank axis on the circular support 28 of the crank web 16 adjacent to the crank journal 12 at the front end of the crank shaft 10. Compared to a normal configuration in which a damper is attached to the front end of the crankshaft 10,
There is an advantage that the overall length of the crankshaft 10 can be reduced, and thus the overall length of the engine can be reduced, so that the mountability on a vehicle can be improved and the weight can be reduced. However, since the damper 30 is stored inside a crankcase (not shown) that houses the crankshaft 10, it operates under different conditions from a conventional damper disposed outside the crankcase.

Therefore, in the damper 30, the inertia ring 36, which is usually made of cast iron, is made of a steel material having high toughness. From the viewpoints of strength, toughness, and processing cost, the steel materials used are carbon steel pipes for machine structural carbon steel ST.
It is advantageous to use KM (JIS: G3445), but other forging steel materials, carbon steel materials for machine structures, etc. can be widely used. In the event that the annular rubber member 34 is damaged by making the inertia ring 36 from steel,
In cast iron rings, the ring itself breaks into pieces during rotation, which in the worst case can cause severe damage to the engine itself, but the tough steel inertia ring 36
Even if the annular rubber member 34 is broken, it keeps the ring shape and rotates, so that the engine itself may be seriously damaged until the driver recognizes the abnormal noise and takes necessary measures. And has the advantage of high security.

Since the damper 30 operates in the crankcase in which the oil is scattered during operation and the splash is full, the annular rubber member 34 is made of a rubber material having excellent oil resistance and heat resistance, for example, acrylic. Rubber (ACM), hydrogenated nitrile butadiene rubber (H-NBR), epichloropidrine rubber (CO), fluoro rubber (FKM), etc. are appropriately adopted, carbon particles and other fillers are added, and the above-mentioned loss factor η = 0 Prepare and use so as to be 0.2 to 0.4. Thereby, sufficient durability can be secured under operating conditions inside the crankcase.

Next, FIG. 10 is a sectional view of a principal part similar to FIG. 3, showing a second embodiment of the present invention. In this embodiment, a sleeve-shaped damper hub 32 is press-fitted onto the circular support portion 28 of the crankshaft. An inertia ring 36 is fixed to the outer periphery of the sleeve-shaped damper hub 32 by baking through an annular rubber member 34. The inertia ring 36 is made of a suitable steel material, and the annular rubber member 36 is made of a heat-resistant and oil-resistant rubber material such as the acrylic rubber and the hydrogenated nitrile-butadiene rubber.

The specifications of the dampers 30 shown in FIG. 10, i.e., the inertia moment ratio _{μ = I d / I e =} 0.05~0.1, natural frequency ratio _{λ = f d / f e =} 0.95~ 1.1, the loss factor η of the annular rubber member 36 is set to 0.2 to 0.4, whereby the torsional vibration of the crankshaft 10 of the four-cylinder engine is reduced to 40 to 70 as in the first embodiment. %, And the operating noise of the engine can be greatly reduced. In addition, since it can be mounted on the crankshaft portion inside the crankcase, for example, the circular support portion 28 provided on the web 16, the total length of the crankshaft 10 is shortened, and thus the total length of the engine is shortened to reduce the weight. In addition, the mountability on the vehicle can be improved, and the durability and reliability of the damper 30 itself can be secured.

FIGS. 11 and 12 show a third embodiment of the present invention.
It is principal part sectional drawing which shows embodiment. As shown, the shape of the damper plate 32 of the damper 30 and the annular rubber member 3
The shapes of the inertial ring 4 and the inertia ring 36 are basically the same as those of the first embodiment, but as shown in FIG. 11, the damper hub 30 is in a free state before the damper 30 is assembled. The disk portion 32b is disposed slightly inclined toward the web 16 with respect to the cylindrical portion 32a. Of course, damper hub 32
An annular rubber member 34 is previously vulcanized and bonded between the disk portion 32b and the inertia ring 36.

The inner diameter of the cylindrical portion 32a of the damper hub 32,
A necessary press-in allowance is provided in advance between the outer diameter of the circular support portion 28 on the web 16 side. As shown by an arrow P in FIG. 11, by applying a pressing force and press-fitting, mainly the joint bending portion between the cylindrical portion 32a and the disk portion 32b is deformed, and the disk portion 32b faces the web 16. Adhere to the side. Since the disk portion 32b is in close contact with the web 16, the vibration of the disk portion 32b is suppressed, and there is no danger of fretting wear. Heat generated due to the torsional deformation of the annular rubber member 34 is in metal contact. Disk part 32b
Through the web 16 to the air and oil in the crankcase.

The inertia moment ratio μ, the natural frequency ratio λ, the annular rubber member 34 of the damper 30 shown in the third embodiment
Of the inertia ring 36 and the annular rubber member 34 are substantially the same as those of the first and second embodiments, and needless to be described again. Advantages and effects substantially similar to those of the second embodiment can be obtained.

The present invention can be implemented by adding various changes and modifications to the first to third embodiments within the scope of the claims.

[0034]

As described above, the damper device according to the present invention includes a damper hub coaxially mounted on the crankshaft of a four-cylinder engine, and an inertia ring mounted on the damper hub via an annular rubber member. I _d : inertia moment of the damper I _e : equivalent inertia moment of the crankshaft system f _d : torsional natural frequency of the damper _fe : torsional equivalent natural frequency of the crankshaft system η: the above when the loss factor of the annular rubber member, the inertia moment ratio _I d _{/ I} e = _0.05~
0.1, torsional natural frequency ratio f _d / f _e = 0.95-1.
1. A compact size that is characterized in that the loss factor η is set to 0.2 to 0.4, and effectively reduces the torsional vibration of the crankshaft of the four-cylinder engine and greatly reduces the engine operating noise. There is an advantage that a damper device that is lightweight and has excellent durability and reliability can be provided.

In the present invention, the inertia ring is made of a steel material and the annular rubber member is made of a rubber material having excellent heat resistance and oil resistance. When installed inside, the durability of the annular rubber member can be effectively ensured, and even if the annular rubber member is broken, the inertial ring does not break, resulting in large damage inside the engine Therefore, there is an advantage that the durability and reliability of the damper can be ensured, and this effect can shorten the overall length of the crankshaft, thereby reducing the weight of the engine and improving the mountability on the vehicle. There are benefits to gain.

[Brief description of the drawings]

FIG. 1 is a plan view partially showing a cross section of a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an enlarged sectional view showing a main part of FIG. 1;

4 is a diagram showing a relationship between a moment of inertia ratio, a torsional amplitude, and a damper weight in a crankshaft having the damper shown in FIG.

FIG. 5 is a diagram showing a relationship between a natural frequency ratio and a crankshaft amplitude in a crankshaft having the damper shown in FIG. 1;

FIG. 6 is a diagram showing a relationship between a natural frequency ratio and a damper relative amplitude in a crankshaft having the damper shown in FIG. 1;

FIG. 7 is a diagram showing a relationship between a natural frequency ratio and a relative amplitude of the crankshaft and the damper in the crankshaft having the damper shown in FIG. 1;

FIG. 8 is a diagram showing the relationship between the maximum torsional amplitude of the crankshaft and the damper and the natural frequency ratio based on the diagram of FIG. 7;

FIG. 9 is a diagram showing a relationship between a loss factor of an annular rubber member and torsional amplitudes of a crankshaft and a damper in the damper shown in FIG.

FIG. 10 is an enlarged sectional view of a main part showing a second embodiment of the present invention.

FIG. 11 is a cross-sectional view of a main part showing a state before press-fitting of a damper hub in a third embodiment of the present invention.

12 is a cross-sectional view of a main part showing a state in which the damper hub has been press-fitted from the state shown in FIG. 11 and has been mounted on the crankshaft.

[Description of Signs] 10 ... crankshaft, 12 ... crank journal, 14 ...
Crank pin, 16 ... crank web, 28 ... circular support portion, 30 ... damper, 32 ... damper hub, 34 ... annular rubber member, 36 ... inertia ring.

Claims (2)

[Claims] 1. A damper having a damper hub coaxially mounted on a crankshaft of a four-cylinder engine and an inertia ring mounted on the damper hub via an annular rubber member, wherein I _d : moment of inertia of the damper. _e : Equivalent moment of inertia of the crankshaft system f _d : Torsional natural frequency of the damper f _e : Torsional equivalent natural frequency of the crankshaft system η: Loss factor of the annular rubber member _d / _Ie = 0.05-
0.1, torsional natural frequency ratio f _d / f _e = 0.95-1.
1. A damper device characterized in that a loss factor η is set to 0.2 to 0.4. 2. The inertial ring is made of steel,
The damper device according to claim 1, wherein the annular rubber member is made of a rubber material having excellent heat resistance and oil resistance.